At times, it is a difficult task to properly secure together a first member to a second member, a replacement part, which is positioned to overlie the first member. This is particularly the case where the first member has a first opening or blind hole extending there-through for receiving a portion of a fastener which will secure the first and second members together. A position needs to be located or established on the second member to machine or bore a second opening through the second member so as to position the first and second holes in alignment with each other. Alignment is needed in order for the fastener to extend through the first and second openings without making binding contact with sidewalls of the first and second openings. This task becomes more challenging with the second member positioned to overlie the first member. The second member or replacement part visually impedes the installer from seeing the first opening or blind hole of the first member thereby making it more difficult to locate a position in the second member in which to machine a new second opening which will align with the blind hole.
Alignment of the first and second openings of the first and second members, respectively, is important. The first and second openings are used to receive a fastener and proper alignment of the first and second openings provide a reliable and long lasting securement between the first and second members. For example, in the instance the fastener is a bolt with a nut, the bolt is positioned to extend through the first opening of the first member and through the machined opening of the second member such that the nut can be tightened to complete the securement. Optimally, the bolt should pass through the first and second openings without binding against either of the inner sidewalls of the first and second openings which extend through the first and second members, respectively. Thus, without the bolt binding to either of inner sidewalls of the first and second openings, the nut can be tightened securing the first and second members together with the nut evenly distributing a force across the nut against a surface of the first member. This even distribution of force prevents an undesired bending moment from being imparted to the bolt.
In working to locate the proper position on the second member in which to machine the second opening or hole through the second member which will align with first opening or blind hole of the first member, an installer may employ a back marking method. The back marking method has the installer reaching behind the first member and extending a marking tool through the first or blind opening to mark a back surface of the second member in alignment with the first blind opening. This back marking method, could provide a guide in which to machine the second opening in the second member to be in alignment with the first blind opening. However, this marking process can be very difficult to accomplish in situations where the first member is positioned in a confined or restricted area making access to the blind hole not readily available. This restricted access not only can make the marking a challenging or impossible task, but even if access can be achieved, this process may also lead to inaccurate marking of the second member.
Inaccuracies in marking the proper location in the second member utilizing the back marking method can arise in extending the marking tool through the first opening or blind hole toward the second member. In an example wherein the first and second members may be spaced apart from one another, the extending of the marking tool through the blind hole toward the second member may encounter the marking tool extending angularly away from a central axis of the blind hole of the first member. The angular extending marking tool will result in marking a position in the second member out of alignment with the central axis of the first opening or blind hole. The subsequent machining of the second hole, in this instance, will position the second opening out of alignment with the blind hole of the first member.
Other methodologies have been employed to locate positions for machining a second opening through a second member, which will overlie a first member. Such methodologies include employing repro-rubber or putty castings. These methods often require confining the rubber or putty substance to form a mold for creating a casting. The rubber or putty material is packed into the confinement which includes the first opening or blind hole of the first member. The casting will indicate a location of the blind hole however, this will only be effective with preservation of the locations of the first member and second members relative to each other. With preservation of the first and second members relative location with one another and the casted location of the blind hole, positioning of the hole to be machined in the second member that will be in alignment with the blind hole may be accomplished. The proper location of placing the second member into position for securement needs to be identified to assure the alignment of the machined hole and the blind hole is accomplished. This is a time consuming process in which inaccuracies as misalignment of the blind hole of the first member and the second opening of the second member can be infused in the process of fastening the first and second members together.